Former state Sen. Robert J. Mellow has been transferred to a federal prison in Georgia.

Mellow, 70, of Archbald, was serving his 16-month prison sentence at a minimum security camp at Federal Correctional Institution-Williamsburg in South Carolina, near Charleston, after his guilty plea last year to conspiracy to commit mail fraud and filing a false tax return.

Federal prosecutors contend he used taxpayer-funded Senate staff to work on his and others' political campaigns.

On Friday, he was moved to Federal Correctional Institution-Jesup, near Savannah, according to Federal Bureau of Prisons records.

FCI-Jesup is a medium security facility that has two adjacent satellite facilities: a low-security facility and a minimum-security prison camp, housing only male inmates.

Mellow is detained in the prison's low-security section, which is a bump up in his security status compared to FCI-Williamsburg, BOP spokesman Chris Burke said Wednesday.

Minimum-security camps have dormitory housing, a low staff-to-inmate ratio and limited or no perimeter fence. Low-security facilities have dormitory or cubicle housing, a higher staff-to-inmate ratio compared to minimum-security camps and double-fenced perimeters, according to the BOP.

Burke declined to say why he was transferred or why he is being held in a low-security facility, citing BOP policy forbidding public disclosure of that information

However, inmates may have their security status changed if they are criminally charged again, especially if it is by a nonfederal agency that wants to make sure an inmate will remain safely detained while the case plays out, Burke said.

Additional charges may also spur an inmate to attempt an escape, Burke said.

In March, Mellow was charged with rigging bids for the Pennsylvania Turnpike Commission. The state charges came while Mellow was in prison for his federal conviction.

On July 16, a Dauphin County district magistrate bound over Mellow for trial on the state case.

An inmate can also be transferred to another prison because of prison work opportunities or disciplinary issues.

Mellow's projected release date on his federal charges -- March 15 -- has not changed, which indicates he has not been disciplined. BOP does not release disciplinary information.

His projected release date gives him credit in advance for good behavior, chipping nearly two months off his 16-month sentence.